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In a recent paper in this journal, the authors have presented a small-contrast perturbation theory of the coherent and incoherent scattering of x-rays from a randomly rough surface. In a Comment on our work, de Boer compares its predictions with those of earlier theories of such scattering. In this reply we argue that several of his comments and conclusions are incorrect owing to an insufficiently careful estimation of certain integrals that occur in our theory.  相似文献   
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The structure of pentagonal particles and the processes of their formation from nanoclusters with the fifthorder symmetry axes are investigated by the methods of computer modeling and scanning electron-ion microscopy using copper as an example. It is demonstrated that the mechanism of cluster growth to pentagonal particles can be realized at which the volumetric stress present in noncrystal clusters will be released without breaking of the fifth-order symmetry of the growing cluster shape. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 27–32, February, 2009.  相似文献   
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Dependences of the dispersion laws and damping of waves in an initially sinusoidal superlattice on the dimensionality of inhomogeneities modulating the period of the superlattice are studied. The cases of one-and three-dimensional modulations, as well as modulation by a mixture of inhomogeneities of both of these dimensionalities, are considered. The correlation function of the superlattice K(r) has the form of a product of the same periodic function and a decreasing function that is significantly different for these different cases. The decreasing part of the correlation function for the mixture of inhomogeneities of different dimensionalities has the form of a product of the decreasing parts of the correlation functions of the components of the mixture. This leads to the nonadditivity of the contributions of the components of different dimensionalities to the resulting modification of the parameters of the wave spectrum that are due to the inhomogeneities (the damping of waves for the mixture of these components is smaller than the sum of the dampings of the components, the maximum gap in the spectrum corresponds to the simultaneous presence of both components of the mixture, not only of the three-dimensional inhomogeneities).  相似文献   
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We present results for the absorption spectrum due to a localized Γ1+ → Γ4? transition that take into account the properties of the linear electron- phonon (e-p) interactions transforming as Γ1+, Γ3+ and Γ5+ in the excited electronic state, in the cases of strong and weak e-p interaction coupling. We show that in the strong e-p interaction coupling limit the asymmetric shape of the structured band is due to the commutation relations of the e-p interaction matrices. Moreover, in the weak coupling limit we present an expression for the spectrum line shape obtained by taking into account the time ordering of the e-p interaction matrices and the phonon propagators at all times. It is shown in the latter case that the densities of phonon states corresponding to the electronic excited state are different from those corresponding to the ground state, and the e-p coupling constants are redefined due to the Jahn-Teller interactions.  相似文献   
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We have calculated the transmission and reflection coefficients for a surface polariton that is incident normally on the interface between two different surface active dielectric media characterized by real, scalar, frequency dependent dielectric functions. Numerical solutions are obtained by matching the boundary conditions for the electromagnetic fields at the interface between the media and between each medium and the vacuum above it. The energy carried away by the vacuum modes is also calculated.  相似文献   
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A theoretical investigation has been carried out on the effect of a drift current on surface polaritons in n-type silicon. The current direction is taken to be parallel to the direction of propagation of the surface polaritons. From the dispersion curves, there is evidence that an interaction takes place between the current and the polaritons which gives rise to polariton instability or amplification for certain frequency ranges. These instabilities are believed to be due to the presence of the surface.  相似文献   
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The dispersion relation for Rayleigh waves on a grating-surface of a semi-infinite, isotropic, nondissipative, elastic medium is solved numerically, with complex wave vector k or complex frequency, in the radiative region (above the bulk transverse sound-line) and within the first frequency-gap on the Brillouin zone boundary created by the grating periodicity. The acoustic attenuation, found from the imaginary part of k, agrees well with experiment. A dispersive branch, with corresponding complex-solutions for the flat surface, between the bulk transverse and longitudinal sound-lines, representing a new leaky mode or surface resonance, accounts for the principal peak in the attenuation.  相似文献   
30.
We present a theory of magnetostatic modes which are wavelike in the direction parallel to the axis of an infinitely long, ferromagnetic bar of square cross-section and are localized at the faces and edges of the bar. We write H = ?▽?, where φ is a magnetic scalar potential, and obtain as the equations determining ?, Σ μαβ?2σ?Xα?Xβ=0 for the interior of the bar, and ▽2? = 0 for the exterior, where μαβ(ω) is the magnetic permeability tensor of the bar. We transform to cylindrical coordinates and solve the resulting second order partial differential equations by assuming a solution for ? of the form ?(r, θ, z) = eiqxf(r, θ). The use of cylindrical coordinates allows us to project out of our expressions for ? the parts which belong to each of the irreducible representations of C4, the group of proper rotations which leave the bar invariant. This has the consequence that the boundary conditions need to be applied along only one side of the bar, and are then automatically satisfied along the remaining three sides as well. The boundary conditions that ? and the normal component of B be continuous across the bar surfaces are satisfied at a discrete set of points along one side of the bar, and two coupled eigenvalue equations are obtained which are solved simultaneously for the frequencies of the corresponding magnetostatic modes. The convergence of this method is found to be quite good. We also present the dispersion curves for the magnetostatic modes of a gyrotropic right circular cylinder which are localized at the surface of the cylinder.  相似文献   
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